YOUNG SCIENTISTS
Hot power
WITH a fridge electricity is used to produce a temperature difference, and as Ramez Tadrous, a fourth year student at Castleknock College, explained, a temperature difference can also be used to produce electricity. This was a discovery that goes back to an early 19th century observation that when two metals are in contact through a closed loop a temperature difference creates an electrical current. These days, said Ramez, semiconductors sandwiched between ceramics can do the same thermoelectric job much more efficiently. Ramez became interested in thermoelectrics when he came across the news that a mobile phone company was planning to produce a charger powered from body heat. “I had never heard about thermoelectrics before,” he said. What surprised Ramez is not so much the idea that the device would be incorporated into a shoe, but that our body constantly produces and loses so much heat. instead of letting that heat go, he said, enough energy could be captured by a thermoelectric device to keep a phone or iPod charged. We don’t always need big amounts of power, he explained, and while the semiconductors used in the sandwich are expensive,
we only need tiny amounts. For small scale devices, he said, thermoelectricity has massive potential, especially where electrical power is hard, or even impossible, to generate. This is why thermoelectrics are so important in space, he said. With the help of his science teacher, Kieran Gallagher, Ramez began investigating these devices, and he presented his results at the BT Young Science and Technology Exhibition. “In an experiment, the maximum temperature difference we got was 160°C, he said , and from this, he was able to generate 1.6 volts. That same device, he explained, could, in theory, produce 3 volts, but the temperature difference would have to be 260°C. As he admitted, that’s quite a difference in te